It is known in the art to provide for control of engine valve lift and timing using a preferably electronic control actuating a solenoid valve to control discharge of fluid from one or more lost motion hydraulic valve actuators driven by an engine camshaft. One such valve timing control system is shown, for example, in the U.S. Pat. No. 4,615,306 Wakeman issued Oct. 7, 1986.
In order to provide soft seating of the engine valves, lost motion actuators for use in such systems have been provided with means for damping the valve seating action as described, for example, in U.S. Pat. Nos. 5,158,048 Robnett issued Oct. 27, 1992, and 5,216,988 Taxon issued Jun. 8, 1993.